   (fn [screen entities]
     (let [screen (update! screen
                     :renderer (stage)
-                    :camera (orthographic :set-to-ortho false
-                                          (/ (game :width) pixels-per-meter)
-                                          (/ (game :height) pixels-per-meter))
+                    :camera (orthographic :set-to-ortho false game-w game-h)
                     :world (box-2d 0 -10)
                     :debug-renderer (Box2DDebugRenderer.))
-          ball (doto {:body (create-ball-body! screen 15)})
-          floor (doto {:body (create-rect-body! screen (/ (game :width) 2) 10)})]
-      (width! screen 20)
+          ball (doto {:body (create-ball-body! screen 1)})
+          floor (doto {:body (create-rect-body! screen (/ game-w 2) 1)})]
+      (width! screen game-w)
       [entities]))
 
   :on-resize
   (fn [screen entities]
-    (height! screen 600))
+    (height! screen game-h))
 
   :on-render
   (fn [screen entities]

  (:import [com.badlogic.gdx.physics.box2d Box2DDebugRenderer]))

(def ^:const pixels-per-meter 30)

(defn create-ball-body!
  [screen radius]
  (let [body (add-body! screen (body-def :dynamic))]
    (->> (circle-shape :set-radius radius
                       :set-position (vector-2 400 500))
         (fixture-def :density 0.5 :friction 0.4 :restitution 0.6 :shape)
         (body! body :create-fixture))
    body))

(defn create-rect-body!
  [screen width height]
  (let [body (add-body! screen (body-def :static))]
    (->> (polygon-shape :set-as-box width height (vector-2 (/ game-w 2) 1) 0)
         (fixture-def :density 1 :shape)
         (body! body :create-fixture))
    body))
